Handling of material samples is commonly done with multi-well plates, i.e., sample holders having multiple individual wells that each hold a discrete sample. Such well plates may be handled using automated systems that subject the material samples to various processes, such as pipetting operations, thermocycling, separation, etc.
In one arrangement, such as that shown in U.S. Pat. No. 6,491,873 and/or U.S. Pat. No. 6,159,368, the wells in a multi-well plate are subjected to a vacuum that causes material in the sample wells to be drawn from the wells and through a filter. For example, a vacuum block or collar may be arranged at a lower side of the multi-well plate so that negative pressure may be applied to a lower end all of the wells in the plate. This negative pressure may cause the material in the wells to be drawn downwardly from the wells through an outlet at the lower end of the wells. The material in the wells may be drawn through a filter element, e.g., positioned in each of the wells, so that some of the material is trapped by the filter while liquid and/or smaller components of the material pass through the filter. The space above the multi-well plate is typically at atmospheric pressure during this process, and thus, the differential pressure that can be created across the wells is typically not greater than atmospheric pressure, e.g., typically less than 15 psi.